Well control head



March 2, 1943. E. J. RoAcH Erm.

WELL CONTROL HEAD Filed Nov. 18, 1941 2 Sheets-Sheet l WW1 L abbe/naafMarch 2, 1943. E. J. RoAcH E-rAL WELL CONTROL HEAD 2 Sheets-Sheet 2Filed Nov. 18, 1941 Y mgllllllllllll Patented Mu. z, 1943 WELL CONTROLHEAD i Edmund J. Roach and Edward F. Cooke, Jr., Beaumont, Tex.

Application November 18, 1941, Serial No. 419,646

7 Claims. (Cl. 285-22) This invention relates to oil well constructionand has for its general object the provision of novel structure forsuspending and sealing an inner casing with respect to a casing head.

One of the specic objects of the invention is to provide a casing headand a slip bowl unit cooperating therewith, said slip bowl unitcomprising a bowl and slips which can be secured to the inner casing atany desired position to seat in the casing head in a duid-tight mannerwhen the inner casing is set so as to prevent leakage of gas underpressure which may develop between the inner and outer casing and toprevent the slip bowl unit from being displaced or blown out by excessgas pressure from the well.

Another object of the invention is to provide a slip bowl unit which maybe drawn from the casing head as a unit on the inner casing when thelatter is drawn up so that the position of the slip bowl unit can bechanged relative to the inner casing if it is desired to alter the depthto which the inner casing is to be set.

Another object of the invention is to provide a packing unit securablewithin the slip bowl and above the slips expansible radially intosealing contact both with the inner casing and with the surrounding wallof the slip bowl by longitudinal pressure positively applied by themeans which secures the slips and packing within the slip bowl.

Other objects of the invention will appear as the following descriptionof a, preferred and practical embodiment thereof proceeds.

In the drawings throughout the several gures of which the samecharacters of reference have been employed to denote identical parts;

Figure 1 is a longitudinal axial section through the upper part of thewell structure illustrating an embodiment of one form of the inventiveconcept;

Figure 2 is a cross section taken along the line 2-2 of Figure 1;

Figure 3 is a cross section taken along the line 3-3 of Figure 1;

Figure 4 is a longitudinal axial section taken through a slightlymodified form of the invention;

Figure 5 is a cross section taken along the line 5--5 of Figure 4;

Figure 6 is a plan view oi.' Figure 4, the inner casing being shown insection;

Figure 7 is a longitudinal axial view through still another modifiedform of the invention;

Figure 8 is a cross section taken along the line l8 of Figure 7; and

iiiil Figure 9 is a cross section taken along the line 9-9 of Figure 7.

Referring now in detail to the several ilgures and ilrst adverting tothat form of the invention shown in the group of Figures 1 to 3,inclusive, the numeral i represents in general a casing head which issuitably secured as by the threaded connection 2 to the upper end of anouter casing 3, it being assumed that the bottom of the outer casing hasbeen firmly cemented in the well and that drilling has proceeded to thepoint of completion at which the inner casing 4 is to be set. The casinghead is provided in the zone immediately above the end oi.' the outercasing 3 with suitable ports 5 which may be either closed by bull plugsnot shown, or connected to a suitable conduit for owing in mud orwithdrawing gas, etc. Above the zone oi the ports 5, the bore of thecasing head is provided with a long downwardly tapered seat 6 and abovethis seat it is preferably cylindrical to the top of the casing head.

A slip bowl unit 'i is received within the casing head having a lowertapering end portion 8 seating upon the tapered portion 6 of the casinghead and provided with ring grooves 9 receiving compressible packingrings .l0 which normally project above the surface of the tapered endportion 8, but are compressed iiush with said surface and against theseat 6 of the casing head either through the weight of the suspendedinner casing or by the upper well equipment whichmay be bolted ortherwise secured to the top of the casing head.

The bore of the slip bowl 1 has a long taper Il in its lower portionbetween which and the inner casing 4 the slips i2 wedgingly seat. Thereare a plurality of the slips i2 arranged at spaced intervals around theinner casing 4, the outer surfaces of said slips conforming to the taperof the lower portion of the bore of the slip bowl and the inner surfacesconforming to the curvature of the inner casing 4 and being preferablyprovided with teeth I3 to give them gripping contact with the innercasing 4.

The upper zone of the bore of the slip bowl is cylindrical and threadedat its upper end.

A packing assembly rests upon the tops of the slips, s aid packingassembly including a metallic junk ring i4 which may be in one or moreparts and above this one or more radially compressible packing rings i5.A metallic follower ring I6 rests upon the top of the compressiblepacking rings and engaged by a ring nut li which has a threadedconnection with the threaded upper and of the bore' of the slip bowlwhereby it may be screwed down upon the pack ing assembly to slide thecompressible packing rings radially into sealing engagement. on the onehand with the inner casing and on the other the slip bowl and the Junkrings and follower rings are similarly provided with threaded aperturesI9 permitting their withdrawal by means of a suitable inserted threadedtool. 'I'he ring nut is provided with suitable holes 2II in its upperend so that a turning tool may be inserted for screwing or unscrewingthe ring nut The upper end of the slip bowl preferably extends a `slightdistance above the planii'orm upper end of the casinghead I to beengaged by the flanged lower end of any suitable piece of upper wellequipment 2I which may be bolted to the flange 22 .of the Yeasing headby the bolts 22 so as'to hold the slip bowl from being displacedupwardly through the `development of excess gas pressure in the space 24between the inner and outer casings.

Inoperation, the inner casing .4 is lowered through blowout preventersinto the bored hole until the approximate amount of inner casing is inplace. The slip bowl unit 1 may then be assembled on t-he inner casing 4on'the outside of the blowout preventers. made up tightly on the innercasing by inserting the slips, the packing assembly and the ring nut andscrewing the latter into tight relation so as to cause the slips to gripthe inner casing and to cause the compressible packing members tosealingly engage the inner casing andl the adjacent wall of the slipbowl. The inner casing with the slip bowl unit thus firmly attached canthen be lowered into the bore until theslip bowl unit seats firmly uponthe tapered seat 8 within the casing head. The weight of the innercasing `compresses the packing rings Ill into sealing engagement withthe casing head. Alternatively, the inner casing may be lowered to theproper point and the slip bowl unit loosely assembled about the innercasing and then released allowing the slip bowl unit to drop freely intothe casing head until it en-l gages the tapered seat 8 of the casinghead.`

Then the slip bowl assembly may be tightened firmly about the innercasing, in situ. In either case the slip bowl unit would pass freelythrough the blowout preventers.

The outside means which have been used to support the inner casing 4 canthen be released and suspension of the inner casing is dependent uponthe engagement of the teeth I3 of the slips I2. While the weight of thesuspended inner casing 4 may generally be relied upon as sufficient toprevent the lifting or blowing out of the slip bowl unit, an extra meansof safety is provided by the clamping engagement of the upper wellequipment 2| with the projecting upper end of the slip bowl. A

In some instances the inner casing will' be cemented firmly in the wellafter it is set, in which case its weight will be taken more or less of!of the slips so that the engagement of the upper well equipment 2| withthe upper end oi asiassr 4. In this construction theA peeking ring 2Uacts as a blowout preventer so that4 the accessoryy blowout preventerswhich are ordinarily pro-- vided on top of .the casing head may beremoved, permitting the slip bowl unit to be tightened while in vsitu inthe casing head with-4 said unit may be out the escape of gas fromthe'weil.

In this form o! the invention the slip bowl unit is positively retainedwithin the casing head independently of any upper weil equipment bymeans of 'a ring nut 21 which surrounds the slip bowl making threadedconnection with the wall of the bore at the upper end .ot thc casinghead and seating upon van external shoulder formed on the slip bowl. Inthis form of the invention the slip bowl and casing head are providedwith cooperating tapering seats, the tapered seat of the slip bowlhaving the ring grooves I in which are seated the packing rings I0. thelatter being pressed into sealing contact with the casing head both bythe weightof the inner casing a and the pressure imposed by the ring nut21 against the external shoulder 2l.

The packing ring 28 may bei'ormed with annular upper and lower grooves29 and 20 which facilitate its deformation into sealing contact bothwith the inner casing 4 4and with the walls of the ring groove 25.

Proceeding now to that formo! the` invention shown in the group ofFigures 6 to 9, inclusive. the casing head lI is similar to that shownin Figure 1, excepting that in a zonc above the seat 6 itis providedwith a plurality or transverse bores 32 having their axes preferably inthe same transverse plane and being threaded as at to receive threadedbolts 34 which may be adjustably screwed inwardly so as tovextend intothe longitudinal bore of the casing head. Said transverse bores arecounterbored at their outer ends and threaded, to receive a stuffinggland comprising a washer 35, packing 28 and a ring nut 31 surroundingthe bolt and threadedly engaging the wail of said counterbore. Thebolts` 'have external polygonal portions 38 or other upon. It has ringgrooves 9 and packing rings ,I0 similar to those shown in Figure 1 anddescribed in connection with that ligure. The inside furnishings of theslip bowl are the same as those illustrated in Figure 1. of the slipbowl has a ferrule 4I suitably secured thereto as by welding, saidferrule carrying in permanent adherence therewith a skirt 42 of flexiblematerial such as rubber or duoprene. The skirt 42 has a lower flared end43 adapting it to be readily slipped over the inner casing. and a-nintermediate cylindrical portion 44 of nor- 'mally smaller internaldiameter than the external diameter of the inner `casing 4. 'I'he saidcylindrical portion of said skirt is expanded by the insertion of theinner casing therethrough so that it presses sealingly against theinnercasing and prevents leakage of gas under well pressure between thewall of said inner casing and i :more` andissealinsiy compressedbytheinner casing.

The lower end l said skirt. This is useful in permitting the slip bowlto' be dropped loosely along the inner casing after the latter has beenset, and the removal of the usual blow-out preventers so that thepacking above the slips can be tightened in situ after the slip bowl isin place in the casing head without the leakage of gas past the slipsduring the tightening operation. Y

'I'he slip bowl 39 is provided with an annular groove 45 above itstapered seating surface 40, the middle of which groove is in the axialplane of the transverse bores when the slip bowl is in.

seated position in the casing head. The ends of the bolts 34 have thesameshape in axial planes as the cross-section of the annular groove 45,so that when said bolts are moved inwardly they fit the annular groove45 and positively hold the slip bowl upon its seat in the casing head.This prevents blowing out of the slip bowl unit by any excess gaspressure which might develop in the well between the inner and outercasings. For removing the inner casing. it is necessary merely toretrack the bolts 45. to apply the accessory blow-Aout preventers to thetop of the casing head and to lift the inner casing. together with theattached slip bowl, through the blow-out preventers by the usualhoisting means. The ring nut I1 may then be removed so as to release thepacking; the slips may be loosened by driving downwardly upon the slipbowl and the loosened parts may then be readily removed.

While I have in the above description disclosed what I believe to be apreferred and practical embodiment of the invention, it will beunderstood to those skilled in the art that the details of constructionand the arrangement of parts as shown and described are by way ofexample, and not to be construed as limiting the scope of the inventionas dened in the appended claims.

What we claim as our invention is' 1. Casing control head for oil wellscomprising a casing head having a planiform upper end and a longitudinalbore with an internal tapered seating shoulder for supporting a slipbowl unit adapted to surround an inner casing, said slip bowl unitincluding a slip bowl with a complementary tapered external seat saidexternal seat being formed with ring grooves and expansible packing insaid grooves `normally extending therefrom adapted to be pressedsealingly against said casing head seat under the pressure of said slipbowl unit, said slip bowl projecting a slight distance above theupperend of said casing head. a member engaging the projecting end of saidslip bowl and bolted to the upper end of said casing head for positivelyholding said -slip bowl unit to its seat and means within said slip bowlcooperating therewith to maintain said slip bowl unit wedgingly fixed tosad inner casing.

2. Casing control head for oil wells comprising a casing head having abore with an internal downwardly tapered seating shoulder for supportinga slip bowl unit, the latter including a slip bowl with a complementarytapered external seat, said external seat being formed with ring groovesand compressible packing in said grooves extending therefrom adapted tobe compressed sealingly against said casing head seat under pressure ofsaid slip bowl unit, said slip bowl having an interior bore with acylindrical upper portion and a downwardly tapered lower portion thelatter portion forming a seat for slips. a plurality of tapered slipsarranged circumferentially within said slip bowl having outer seatingsurfaces said slip bowl comprising a `iunk ring resting upon said slips,radially expansible packing above said `iunk ring and a ring nutscrewing into said bowl against said packing for expanding it againstsaid bowl and said inner casingand for y wedgingly forcing said slipsinto engagement with said inner casing.

3. In a casing control head, means for pending an inner casing in acasing head comprising a slip bowll unit including a slip bowl with. anexternal downwardly tapered seat for seating upon a complementaryseatingshoulder in a casing head, said slip bowl having anvinterior borewith a cylindrical upper portion and a downwardly tapered lower portionthe latter portion forming a seat for slips, a plurality of taperedslips arranged circumferentially within said bore having outer seatingsurfaces complementary to the tapered portion of the slip bowl bore andhaving inner cylindrical faces complementary to the surface of an innercasing which the slip bowl is adapted to surround, for wedginglygripping said inner casing, and a packing unit in the cylindricalportion of thebore of said slip bowl comprising a junk ring resting uponsaid slips, radially expansible packing above said junk ring, and a ringnut screwing into said bowl against said packing for expanding itagainst said bore and the inner casing and for forcing said slips intoengagement wlthsaid inner casing. Y

4. Casing control head for oil wells comprising a casing head having abore with an internal downwardly tapered seating shoulder in its lowerportion for supporting a slip bowl unit, a cylindrical intermediateportion and an upper threaded cylindrical portion of larger diameterthan said intermediate portion, in combination ing an upwardly facingexternal shoulder inthe zone of the upper cylindrical portion -of thebore of said casing head, and a ring nut surrounding the upper part ofsaid slip bowl engaging said upwardly facing shoulder and screwing intosaid casing head for positively holding said slip bowl unit upon itsseat in the casing head.

5. In a casing control head for oil wells, means for suspending an innercasing in a casing head comprising a slip bowl unit including a slipbowl with an external downwardly tapered seat in an intermediate zonefor seating upon a complementary seating shoulder in a casing head, andhaving a longitudinal bore with a downwardly tapered seat in the samezone as said external seat, a plurality of tapered slips arrangedcircumferentially within said slip bowl hav-lng outer seating surfacescomplementary to the surfaces of said internal seat and having innercylindrical faces complementary to the surface of an inner casing whichthe slip bowl is adapted to surround, upper packing abovev said slips,means for expanding said packing in sealing relation to said innercasing, said slip vbowl having a lower portion below said internal seatand an annular nexible packing element carried by said lower portionsurrounding said inner casing of normally smaller internal diameter theexternal diameter of said inner casing.

vingleakage between said inner casing and slip bowl unit until the saidupper packing has been asians? s 6.' In acasing" control head foroil-wells. means ltor suspending an inner casing in a casing headcomprising a slip bowl unit including aslip bowl with an externaldownwardly tapered seat in anintermediate sone for seating upon acomplementary seating shoulder in a casing head, and having alongitudinal bore with a downwardly tapered seat in the same sone assaid external seat. a plurality of tapered slips arrangedcircumferentially within said slip bowl having outer seating surfacescomplementary to the surfaces ing sealingly pressing said inner casingfor preventing leakage between said inner casing and said slip bowl unituntil the upper been expanded.

'1. Casing control head for oil wells comprising a casing head having alongitudinal bore with an internal downwardly tlvered seating shouldertor supporting a slip bowl unit and having threaded transverse bores ina sone above said seating shoulder communicating with said longitudinalbore. said slip bowl unit including a slip bowly with an externaldownwardly tapered seat complementary to the surface of said seatingshoulder. provided with ring grooves and compressible packing in saidring grooves normally extending therefromand adapted to be compressedsealingly against said seating shoulder under pressure oi said slip bowlunit, said slip bowlhaving an external annular groove above saidexternal tapered seat and in the transverse plane oi' the transversebores of said casing head when said slip -bowl unit is seated in saidcasing head, bolts screwing into said transverse bores engaging saidslip bowl unit within said groove for positively holding said slip bowlunit upon its seat in the casing head,

and stumng glands in said transverse bores seal,- ingly engaging saidbolts.

EDMUND J. ROACH.

EDWARD F. COOKE, Jn.

mill!"

